A5079833850- GaN-based semiconductor devices and materials
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- ZnO doping and properties
- Nanowire Synthesis and Applications
- Surface and Thin Film Phenomena
- Ga2O3 and related materials
- Thin-Film Transistor Technologies
- Anodic Oxide Films and Nanostructures
- Acoustic Wave Resonator Technologies
- Advanced Semiconductor Detectors and Materials
Chemnitz University of Technology
2022-2025
Lateral ambipolar diffusion in an InGaN/GaN single quantum well (SQW) structure grown on bulk GaN is studied by microphotoluminescence (μPL) investigations. The analysis done via pinhole scans, that is, decoupling the excitation area from detection and scanning latter one. Knowing size of excited region, conclusions about carrier transport in‐plane layer QW can be drawn. In this study, a length up to 12 μm observed at room temperature. Furthermore, energy spectral peak analyzed as function...
We analyze the time-resolved photoluminescence (PL) from bulklike continuum of excited states 450 nm emitting InGaN/GaN device structures that are based on wide quantum wells with 25 thickness. In its spectrally integrated form, PL behaves as if it were dominated by radiative recombination, including an almost exponential decay reflecting lifetime. If is resolved spectrally, a very broad spectrum time constants found, ps to ns. At low temperatures, we detected fast (16 ± 2) ps. This assigned...
A micro-photoluminescence setup is used to investigate the ambipolar diffusion of charge carriers in InGaN quantum wells (QW) grown by molecular beam epitaxy. The thickness active region varies between 2.6 and 25 nm. Our results show for all samples range a few μm. Additionally, larger QW accompanied smaller luminescence spot radius our experiment. However, dark carrier with increasing cannot be excluded due an lifetime. Moving away from excitation center leads stronger tilt potential lower...
By combining microscopy investigation, light-beam induced current (LBIC), micro-photoluminescence ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> -PL), and micro-electroluminescence -EL) characterization, we investigate the electrical optical properties of V-pits trench-like defects in high-periodicity InGaN/GaN multiple quantum wells (MQWs) solar cells. Experimental...
The growth of high In content InGaN material is notorious for being challenging because mechanical strain and thermodynamic instability the system. It has been shown that one can improve quality by using variable surface miscut. this study, we demonstrate use micropatterning bulk GaN substrates in order to layers. During MOVPE layers depends on local shape substrate surface, reaching highest emission intensity at top every pattern. We study patterns with characteristic sizes ranging from 1 6...
Micro-photoluminescence (μPL) pinhole scans of an InGaN multi-quantum well (MQW) and single-quantum (SQW) LED structure show large PL spots compared to the relatively small excitation area. We observe a lateral diffusion over wide range in order 10 µm both samples. The density is varied identify dependence length on amount injected charge carriers. Overall MQW sample shows smaller SQW sample, which attributed different quality. In no significant change with varying power observed, whereas...
Degradation of GaN-based laser diodes after some time operation appears usually as raised threshold current, lower slope efficiency, or increased voltage. We investigate stressed and non-stressed using micro-electroluminescence (μEL) micro-photoluminescence (μPL). In μEL, the device exhibits darker regions, which are correlated with a red-shifted emission. Both observations indicate carrier density in these areas. Our μPL measurements do not suggest corresponding defect regions. This study...